1. Field of the Invention
The present invention generally relates to a tone synthesizing method, a tone processing method, and a tone synthesizing apparatus that is suitable for use in the tone synthesis based on software.
2. Description of Related Art
Various software programs are known for tone synthesis on computer systems. In these software programs, various tone generator modules such as FM tone generator, PCM tone generator, and physical model tone generator are provided, and tones synthesized by these modules are mixed together, thereby providing a desired tone signal.
The above-mentioned tone synthesizing technology requires to set the sampling frequencies of various modules to a common level. This makes it difficult to adopt those modules (for example, the physical model tone generator) which hardly operate with sampling frequencies other than a specific one. This prohibits users to use high-quality modules only because of discrepancy in sampling frequencies. Consequently, it has been difficult to achieve high-quality tone synthesis.
Further, if CPU power runs short in software-based tone synthesis, some countermeasures must be taken, such as partially skipping the tone synthesis processing for example. However, the conventional software cannot properly determine which part of the processing is to be skipped. This may inadvertently skip an essential processing operation, thereby significantly lowering the tone quality.
Still further, the conventional software-based tone synthesis frequently executes processing in some collective units (called a frame) because it is inefficient to execute the processing on a sample by sample basis. However, in imparting two or more sound effects in this frame-based processing, an improper imparting sequence may not provide sufficient sound effects. The sequence of applying the different effects is not considered in the conventional tone synthesizing software, thereby degrading the quality of synthesized tones.